Hepatitis is an inflammation of the liver, most commonly caused by a viral infection. There are five main hepatitis viruses, referred to as types A, B, C, D and E.
Hepatitis A and E are typically caused by ingestion of contaminated food or water. Hepatitis B, C and D usually occur as a result of parenteral contact with infected body fluids (e.g. from blood transfusions or invasive medical procedures using contaminated equipment). Hepatitis B is also transmitted by sexual contact.
Worldwide, it is estimated that 400 million people are chronically infected with hepatitis B virus (HBV). Chronic hepatitis B (CHB) infection is the most common cause of liver cirrhosis and hepatocellular carcinoma (HCC), with an estimated 500,000-900,000 death per year. Continuing HBV replication increases the risk of progression to cirrhosis and HCC (28-31).
Variations in the hepatitis B virus (HBV) genome may develop spontaneously or under selective pressure from antiviral therapy. Some of these variations confer drug resistance, resulting in treatment failure which may further lead to hepatitis reactivation and hepatic decompensation (32).